Excel 2007 : Create an input out output application in Excel for selling water

Hi,

I posted the same question on another board but since it's more of a project and I'm not really in a situation (read: living in ramen noodles world..) where I can pay for a solution the topic got closed ( http://www.ozgrid.com/forum/showthread.php?t=145753 ).

So, I thought that maybe I could try to find someone here.

In Short:
My parents bought a water-bottle-refill store a few days ago and I was just there and saw that they are tracking everything on a piece of paper that they then have to add up and tie to the cash register - and getting any 'statistics' from the sales is near impossible and/or very hard to do.

So...I thought I was going to be a good daughter and see if I couldn't bring them into the modern days and get them a used laptop and set them up with something that would be easier for them to track - and USE the data they are collecting

The challenge:
I'm not very good with spreadsheets/access databases myself..so as I said I thought I'd see if there would be a helpful soul here that might be willing to help out.

What they are doing now:
They sell two kinds of water:
- 25cents per gallon, and
- 45cents per gallon.

People can pay either by cash - or a 'prepaid membership card'.

They have a piece of paper with basically four columns:
C25, C45, M25, M45
(Cash 25c, Cash45c, Membership25, Membership45)

If someone comes in and buys, say, 5 gallons of the 25cent wanter and pay in cash - they put a '5' in the column named 'C25'. End of the day the add up all the columns and see if it ties to the cash register.

The reason they 'break out' the 25, 45, cash and membership is to see what sells and how (do they need the membership, is the more expensive water in demand, etc).

The Challenge:
Input:
I would love something easy to use but that looks 'professional'
I'm not sure if one can make a 'front-end' or 'form' maybe where they would just pick the cash/member/25/45 with checkboxes (or something) and then type in the gallons.
Something that's easy to use and for people that can't read text tooo small

Output:
I think this is maybe the real challenge.
I would love to be able to help them by giving them tools that could show them for instance;
- the total for the day,
-the total for the week,
- totals BY say member/cash,
- totals BY cash or membership,
- any total for a certain day/time period you type in,
- Etc

Maybe in text..maybe in like pie charts..I am not sure

Is this something anyone out there have an idea about how to do (including the 'form-frontend')?

I can't really offer any money as compensation (unemployed and soon, if things doesn't look better working in my parents waterstore ) - but maybe there is something to say for good karma.

Anyone.....?

/Tiff